In computer networking, network address translation (NAT) is the process of modifying network address information in datagram (IP) packet headers while in transit across a traffic routing device for the purpose of remapping one IP address space into another.

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790 views

DNAT port range with different internal port range with Iptables

The standard way of DNATing a single port to a different port on an internal network is something like that: ip(6)tables -t nat -A PREROUTING -i wan0 -p tcp --dport 80 --to-destination 10.0.0.1:8080 ...
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1answer
17 views

Does STUN work on majority of NATs?

I've been largely ignoring STUN protocol as noise for a while, but I keep encountering it here and there, and I'm wondering of it's general usability. If I understand it right, STUN is only useful if ...
0
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1answer
79 views

AWS - HA - Multiple NAT - Single EIP

According to the AWS docs it is possible to setup HA between two EC2 instances, however I would like to use only a single EIP. If you scroll down the page to the section related to elastic ips, the ...
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0answers
28 views

Can potential conflicts arise between IPtables port blocking and NAT port translation?

I have set my iptables rules to open only some ports for outgoing connections. I also have snat iptables rules to do NAT which I presume will do a local IP to public IP and also a port translation, ...
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0answers
45 views

Trouble for enable NAT for virtual interface tap0 on Linux

Hi I am having trouble for enable NAT for virtual interface tap0 Situation described as below: I have eth0 interface which has internet i.e ping -I eth0 google.com works Now I have created virtual ...
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2answers
794 views

Do I need a managed switch for my home network? [closed]

The benefit to home routers is that all you need to do is plug them in, and they pretty much work out of the box, allowing multiple computers to use a single internet connection. Let's say I wanted ...
2
votes
1answer
289 views

Does the ELB also route outbound reply traffic in AWS

I have been trying to understand how routing works in an AWS VPC with public/private subnets. I have a setup as recommended by amazon with an ELB and NAT in the public subnet and the webserver in the ...
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0answers
28 views

Cant configure NAT in iptables

Есть два сервера с линукс. Первый выполняет роль роутера, он имеет два сетевых интерфейса, один из которых подключен к интернету, другой к локальной сети. Второй сервер подключен к локальной сети. ...
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0answers
92 views

CentOs 6 as Firewall, forward traffic from eth1 to eth0 -> destination host prohibited

I'm setting up Firewall with a CentOs 6.0 for testing. I'm doing this on two virtualmachines. First VM (Firewall) has 2 interface: eth0 - connected to NAT with 10.0.2.10, access to internet eth1 - ...
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0answers
113 views

iptables POSTROUTING DNAT Issue

So I am attempting to do something along these lines but hopefully with a single router instead of two. My network is as follows: Device 1 <--> (Interface A | Interface B) <--> Device 2 ...
1
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1answer
61 views

GNU parallel multpile sshlogin nodes behind NAT

Is it possible to have multiple remote nodes behind a NAT with GNU parallel? Suppose some of a GNU parallel cluster exists behind a NAT (which may or may not be accessible only via a single IPv4 ...
0
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1answer
50 views

Iptables won't redirect

I'm trying to redirect all tcp traffic on port 102 from a single ip address to another ip address and want to masquerade the ip as well im using this iptable config, but still i cannot connect. ...
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0answers
63 views

No web access behind Cisco Router - Connection denied due to NAT reverse path failure

I have a small network behind a Cisco ASA 5505. From a computer on the network, I can't even ping 8.8.8.8. Web browsing also fails with a "DNS probe finished no internet" error. I'm getting a lot of "...
1
vote
1answer
634 views

How can I place a Webserver in a private subnet in AWS and open it to the world on port 80

I am trying to setup a highly available AWS Magento deployment. There is a reference deployment here: http://docs.aws.amazon.com/quickstart/latest/magento/architecture.html Based on this, I want to ...
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0answers
79 views

iptables - forward traffic to VPN client

Following Scenario: Router forwarding traffic on port 80 to Machine A Machine A 192.168.0.254 Running Owncloud on port 80 Connected to VPN Provider Machine B 192.168.0.123 can connect to ...
1
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1answer
27 views

How to diagnose what is causing all request to websites hosted on internal network to be redirected to router?

On internal network I have a client and a server. Server is hosting example.com and fake.example.com that are also open to the internet through NAT. Any computer on the internet can access example.com ...
0
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1answer
59 views

Public to Public NAT/Routing

We have a set of web services available to our customers. Many of our customers have firewall/proxy exceptions setup to our public IP address. We need to expand and move to a new location. Part of ...
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2answers
121 views

How to workaround a IP whitelist when consuming a 3rd-party API?

We use a service who's API will reject requests unless the source IP has been previously whitelisted. They only give us 3 slots which is a problem because we have more than 3 machines that need to use ...
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0answers
98 views

cisco 1800 series NAT with secondary IP

I have some troubles doing NAT. If I set up NAT for a particular port, the server replies, but it does so from a different IP address, (specifically from the main IP). If I set up NAT to B.B.B.B, the ...
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0answers
608 views

Cisco ASA 5505 cannot ping from inside to outside

Hi everyone and thanks in advance for all the help. I'm having some issue getting my cisco firewall (asa 5505) to ping between zones. The inside zone won't ping with the outside zone and vice versa. ...
0
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0answers
66 views

How to implement 1:1 (mapping)NAT like aws does mapping public IP to private IP

I have a machine in private network having it's private IP (lets say 192.168.1.8). I have one server somewhere having public ip (lets say 1.2.1.2) I would like to map this public IP to my private IP ...
4
votes
1answer
196 views

Finding google unusual traffic

We are a small Internet provider. In order to get Internet access we are using NAT (10-20 users per one public IP). And lately we've met with Google blocking services (captcha and full block) and we ...
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0answers
46 views

iptabels stcp packet not reach nat table

i want to forward sctp packet to my internal network. then i configure forward with -p sctp in nat table. but i found it not work at all. then i add some log to track to see what happen. it's ...
0
votes
1answer
50 views

iptables 1:1 NAT with rules for individual services

I have a working 1:1 NAT setup on CentOS 6.7. But I do not yet have access rules set for various services. How would I enable access to TCP/3389 on the host currently sitting on 192.168.0.149, ...
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0answers
191 views

web server behind NAT cannot be accessed by the same network using NAT router IP or domain

I have 1 host server as NAT server, it has public domain name example.com tied to its public IP address PUB_IP_ADD. I have another web server behind NAT with IP address 192.168.1.100 and port ...
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0answers
30 views

ubuntu router intermittently times out

I have an ubuntu 14.04 server working as an internet gateway/router. When I run a continuous ping against a known good address on the internet, I get steady reply with good latency. But sometimes when ...
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0answers
203 views

Asterisk recieves 403 on every outbound call after 5 minutes delay

I have a home server in my local network with Asterisk installed. It has been working without any problem for several month. I have just changed my router (ZyXel Keenetic Lite -> LP-LINK TL-R480T+) ...
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1answer
102 views

AWS Private subnet not redirected to NAT Instance

AWS is not setting up properly default gw for instance in private subnet. NAT address: ec2din i-ef7f8a3a|grep PRIVATEIPADDRESS PRIVATEIPADDRESS 172.16.0.31 ROUTING TABLE configuration: ec2drtb ...
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1answer
202 views

Is it possible to set up WAN connection on a VLAN (Cisco Router)?

I'm trying to set up NAT load balancing (or failover) with two ISPs on my 1941 router. The router has only two WAN ports and 4 EHWIC ports (which are basically switch ports). One of the WAN ports is ...
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0answers
147 views

NAT problems with OpenVPN + PF OpenBSD

I rented a server to use as a VPN for educational purposes , ok so set up openvpn server and its all working. I can connect to it with my Windows 7 laptop but i won't be able to browse any website ...
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0answers
83 views

Unable to connect to web server hosted in private subnet of VPC via NAT hosted in public subnet

I have hosted my android/web application on a EC2 instance in the private subnet (10.0.1.0) of my VPC. This instance has apache-tomcat installed on it, but does not have a public IP. I also have a ...
1
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1answer
159 views

Asterisk behind Cisco ASA 5505

I'm in the process of upgrading from an old WRT54GL running Tomato to a Cisco ASA 5505, versioning as follows: Cisco Adaptive Security Appliance Software Version 9.1(5)21 Device Manager Version 7.4(...
1
vote
1answer
41 views

IP Address secondary transpose

I am bit new to cisco and I have assigned 5 static IPs to my serial interface 0/0. I have NATed email in via one of the secondary IPs to the server. However, when I try to send mail out it's sending ...
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0answers
25 views

Vyatta Nat Rule Help Translating From Cisco ASA Rule

I'm fairly new to Vyatta and need advice on how to translate the following rule example from a Cisco ASA to the Vyatta. static (dmz2,outside) 192.168.254.0 192.168.254.0 netmask/24 How do I ...
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0answers
124 views

RTPProxy traversal does not work wit Opensips

I installed opensips but there is no sound on clients. This is what I did: apt-get install opensips rtpproxy osipsconfig I selectred Nat Tracversal and generated the .cfg file. The customized ....
3
votes
1answer
56 views

Cisco IP Redirection (static NAT?) for non existant IP Range

We are moving office and our managed service provider has let us down badly. We have a Cisco 4500 stack with 5 VLANS configured of interest. These are: interface Vlan200 description FLOOR0 Gateway ...
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0answers
98 views

Error: Can't create new inside entry - forced_punt_flags: 0

I have a router Cisco 3725 and setup NAT on this but when I run command debug ip nat detailed it show error "Can't create new inside entry - forced_punt_flags: 0" My router config as follow: Current ...
2
votes
1answer
274 views

pfSense can't access https website

I have just installed pfSense on a PC Engines APU1D4 to evaluate as an alternative to a Soekris 5501 + OpenBSD based setup, I have a PPPoE WAN configuration. The pf rules, NAT and PPPoE ...
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0answers
26 views

How to communicate effectively over a jumphost?

My company uses a jumphost to get into a datacenter. For various reasons I want to use applications that communicate from my localhost, to ports on a machine or set of machines in that datacenter. ...
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votes
1answer
302 views

How to make VMs get LAN IPs from ESXi 6 Host

I have a very simple setup where my ESXi host is hooked up to the LAN just as other regular PCs. I have created a few VMs on that host and want to be able to access the LAN as if these were hooked up ...
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0answers
33 views

Expert iptables Nat - Virtual interface ip address issue

I've been looking information related to this problem several days, I had no luck finding a concrete explanation. Explanation about this issue: With this command I redirect one ip to another ip in ...
3
votes
4answers
2k views

pfSense not forwarding back packets

I have a pfSense box setup where my WAN interface (em0) is set up in my local network (192.168.1.100) and my LAN interface (em1) is a private network of its own (10.0.0.1). The end goal is to have the ...
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vote
0answers
140 views

tcp previous segment not captured when NAT

I have a client request web service on a server behide NAT. My client IP is 10.54.10.193 NAT address: 10.54.28.183 Server address: 62.209.39.203 When client request web service on server we have TCP ...
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0answers
55 views

ASA 9.1 NAT Rule issues

I added this NAT rule on my 5510 ASA object network SHF-NY-DC01 host 192.168.1.50 nat (Inside,Outside) static interface service tcp ldap 6699 access-list inbound extended permit tcp any object SHF-...
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0answers
15 views

How does NAT work with more than 2^16 devices? [duplicate]

According to this article, NAT keeps track of which devices to route responses to by specifying a response port that it listens on. For example, when I make a request from a NATted computer, my router ...
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1answer
62 views

forwarding from internal to external network does not work

I have a Ubuntu 14.04 LTS server with two NICs. One is connected to the internal network (eth0, 192.168.4.0/24) and the other one is connected to a router with internet access (eth1, network 192.168.2....
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2answers
378 views

Bind docker container ports only to specific outside server address

This is the first time i address such a network "problem" to solve with docker and i need some inputs. This is my situation: Ubuntu 14.04 running NginX, ufw as firewall and docker containers to ...
0
votes
1answer
23 views

public tunnel into private behind-nat machine

Say I have a web server running on my local machine which is connected to the internet but behind NAT (let's just assume it cannot be reached directly from the outside but It can open TCP/UDP ...
0
votes
2answers
844 views

Hyper-V host with one External IP address. How do I assign guest VMs an internal IP and configure NAT?

I've been struggling with this for a few days now, I've got a Hyper-V host with one statically configured external IP address. There is no DHCP server or internal network to retrieve an IP. How do I ...
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2answers
90 views

Trying to hookup 10-15 laptops to a switch, could someone point me in the right direction?

Let me start off by saying I am not a system administrator, however I am desktop client support. I have the need to have about 10-15 laptops to be hooked up to a switch that gives all 10-15 laptops ...